Peter Xu <peterx@xxxxxxxxxx> writes: > On Thu, Jul 11, 2024 at 10:34:12AM -0300, Fabiano Rosas wrote: >> Is there an easy way to look at a field and tell in which machine type's >> timeframe it was introduced? > > I am not aware of any. > >> If the machine type of that era has been removed, then the field is free >> to go as well. I'd prefer if we had a hard link instead of just counting >> years. Maybe we should to that mapping at the machine deprecation time? >> As in, "look at the unused fields introduced in that timeframe and mark >> them free". > > We can do that, but depending on how easy it would be. That can be an > overkill to me if it's non-trivial. When it becomes complicated, I'd > rather make machine compat property easier to use so we always stick with > that. Currently it's not as easy to use. > > Maybe we shouldn't make it a common rule to let people reuse the UNUSED > fields, even if in this case it's probably fine? > > E.g. I don't think it's a huge deal to keep all UNUSED fields forever - > sending 512B zeros for only one specific device isn't an issue even if kept > forever. > > If "over 6 years" would be okay and simple enough, then maybe we can stick > with that (and only if people would like to reuse a field and ask; that's > after all not required..). If more than that I doubt whether we should > spend time working on covering all the fields. I'm fine with a simple rule. But of course, that means we cannot claim to support all kinds of forward migrations anymore. Only those in the 6 year period.
